It’s the time of year where you start making to-do lists for the winter, where you nail down things you want to fix.

For the Twins and Scott Diamond, Tuesday reminded them of a couple of big offseason projects: Cutting down on strikeouts at the plate, and figuring out Target Field on the mound.

The Twins struck out 14 times against the Tigers, the 10th time they’ve had that many or more in a game this year, and Diamond gave up three more home runs in his home park, helping Detroit clinch a playoff spot for the third consecutive season with a 4-2 victory.

But for a couple of dramatic ninth-inning home runs — one by Brian Dozier on Monday, one by Indians’ pinch-hitter Jason Giambi in Cleveland on Tuesday — the Tigers would have soaked their clubhouse in champagne, celebrating the American League Central Division championship. With their magic number down to one, that party could come in Wednesday’s series finale, when Cy Young favorite Max Scherzer makes his final tuneup for next week.

Meanwhile, the Twins will mull over a season’s worth of missed chances and costly mistakes, with Tuesday’s loss simply adding to the pile. They went 1-for-10 with runners in scoring position, which is getting to be normal around here. But Gardenhire was disappointed that in each of the first three innings, the Twins put a runner on third base with one out, and all three times, they failed to produce even a fly ball to drive him home. Josh Willingham was the culprit twice, and Clete Thomas once..

Dave Denney

Gallery: Detroit 4, Twins 2

And the strikeouts are simply driving him crazy.

“Fourteen strikeouts. You can’t do that. It’s hard to win baseball games when you do that,” the Twins’ manager said, though oddly, Minnesota is actually now 5-5 when they do. “They’re not trying to, believe me. They’re trying to hit the ball. Swinging and missing is one thing, but taking pitches for called third strikes is the disappointing part.”

Eight of the Twins’ last nine outs came via strikeouts, a day after 10 of the Twins’ first 11 outs were also whiffs.

As for Diamond, he pitches half his games in the American League’s most difficult park to hit a home run, yet he somehow makes Target Field look like a bandbox. The Twins’ lefthander pitched well most of the time Tuesday, working out of trouble, retiring eight in a row at one point, looking like the hard-to-hit savant he frequently seemed to be last year.

But in the top of the fourth, all his skills abandoned him, and his nick-the-corner methodology abruptly dissolved into down-the-middle meatballs. Victor Martinez placed Diamond’s errant fastball just inside the left-field foul pole. Omar Infante deposited Diamond’s misplaced changeup about two sections to the right. And Austin Jackson, with a runner on first, simply cannoned a curveball into the Tigers’ bullpen, capping a four-run, out-of-character meltdown for Diamond.

“Everything kind of comes in clumps for me,” Diamond said. “It’s been that way all season.”

Especially in Target Field. The Twins’ downtown ballpark has witnessed the fewest home runs in the American League this season, and ranks 26th in the major leagues. Yet somehow Diamond, who has surrendered 14 home runs here, ranks among the A.L.’s top 10 for home runs allowed at home. He’s 2-9 in Minneapolis and 4-3 in other parks.

It’s not just this year, either. In his three-year career as a Twin, the Canadian has allowed 26 home runs in Minnesota and 14 everywhere else, despite a difference of only 12 innings in usage. Diamond’s ERA is 4.66 at home, 4.25 on the road.

That’s a problem Diamond must conquer if the 26-year-old wants a spot in next year’s rotation, because Target Field should be helping, not hurting, him.

“Maybe it means I’m pitching too much in, then I’m missing too much over the plate,” he shrugged. “I’ve got to find that fine balance here.”